An Optical transport network (OTN) is a core technology in a transport network. The OTN has a great Operation Administration and Maintenance (OAM) capability, a strong Tandem Connection Monitoring (TCM) capability, and an out-of-band Forward Error Correction (FEC) capability, and can implement flexible grooming and management of a large-capacity service.
With the growth and diversification of service traffic, an OTN with a fixed-rate interface can no longer meet an interconnection requirement. Currently, the International Telecommunication Union—Telecommunication Standardization Sector ITU-T) is formulating an n×100 G Flexible OTN (FlexO) group interface. Based on n 100 G optical modules, the FlexO group interface provides a flexible-rate interface to carry a signal of an Optical Transport Unit-Cn (OTUCn), so as to implement an interconnection between OTUCn signal inter-domain interfaces. The n×100 G FlexO group interface includes n 100 G FlexO lanes, and a rate of each FlexO lane is equal to an OTU4 rate. In this case, each 100 G FlexO lane can directly use a standard and low-cost 100 G optical module (such as CFP4 or QSFP28) for sending. As shown in FIG. 1, an OTUCn is first divided into n OTUC client signals, and the n OTUC client signals are marked as #1, . . . , and #n; a one-to-one correspondence is established between the n OTUC client signals and n lanes of FlexO frame signals (the OTUC client signals #1, . . . , and #n are respectively and synchronously mapped to payload areas of FlexO frames #1, . . . , and #n); a physical channel identifier (PID) of FlexO frame overheads is used to indicate a location of a current FlexO lane in a FlexO group, and correspondingly, a location, in an OTUCn, of an OTUC client signal carried in the current FlexO lane can be obtained (an OTUC instance in the diagram is an OTUC client signal). FIG. 2 shows a corresponding frame structure.
A defect in the prior art is that, a service cannot be flexibly transmitted due to one-to-one mapping between the n OTUC client signals and the n lanes of FlexO frames.